Concurrency issue with TimeZoneConverter

Version

4.19.2

Describe the bug

Intermittently we are seeing a concurrency issue when trying to use date based adaptive functions.

It seems to stem from concurrent access of static dictionaries in TimeZoneConverter.

To Reproduce

To reproduce you can follow the following steps. Note step 3 is not easy to reproduce and requires some load:

1. Having a bot using the adaptive function convertFromUTC in the first turn. e.g. =float(formatDateTime(convertFromUTC(utcNow(), 'Eastern Standard Time'), 'HH'))
2. Then restarting the process hosting the bot code
3. Having concurrent requests hit our bot which both cause the static dictionaries in TimeZoneConverter to be initialized - causing the error below which stops the bot from functioning:

System.InvalidOperationException

AdaptiveExpressions.TimeZoneConverter.LoadData

Operations that change non-concurrent collections must have exclusive access. A concurrent update was performed on this collection and corrupted its state. The collection's state is no longer correct.

Expected behavior

The dictionary access in TimeZoneConverter should be thread-safe.

Screenshots

N/A

Additional context

N/A

[jamesemann]

Thanks team for prioritising this. I will keep an eye out for the new release Monday

[tracyboehrer]

@robertcox-msft It will be available on NuGet within minutes of the release. We will do a Release on GitHub. Anyone watching the repo will get notified. We don’t have any other mechanism to notify.

It won’t be until Monday at the earliest though.